Abstract
Low-fat, healthy yogurt is becoming increasingly favoredby consumers. In the present study, whey proteinemulsion gel microparticles were used to improve thequality of low-fat yogurt, and the effects of vegetableoil emulsion gel as a fat substitute on the qualities oflow-fat yogurt were investigated, expecting to obtainhealthier and even more excellent quality low-fat yogurtby applying a new method. First, emulsion gelmicroparticles were prepared, and then particle sizedistribution of emulsion gel and water holding capacity(WHC), textural properties, rheological properties, microstructure,storage stability, and sensory evaluation ofyogurt were carried out. The results showed that yogurtwith emulsion gel had significantly superior qualitiesthan yogurt made with skim milk powder, with betterWHC, textural properties, rheological properties,and storage stability. The average particle size of wheyprotein-vegetable oil emulsion gel microparticles wassignificantly larger than that of whey protein-milk fatemulsion gel microparticles, and the larger particle sizeaffected the structural stability of yogurt. The WHC ofyogurt made with whey protein-vegetable oil emulsiongel microparticles (V-EY) was lower (40.41%) than thatof yogurt made with whey protein-milk fat emulsiongel microparticles (M-EY; 42.81%), and the textureresults also showed that the hardness, consistency, andviscosity index of V-EY were inferior to these of M-EY,whereas no significant differences were found in thecohesiveness. Interestingly, the microstructure of V-EYwas relatively flatter, with more and finer networkbranching. The whey separation between V-EY andM-EY also did not show significant differences duringthe 14 d of storage. Compared with yogurt made withwhey protein, vegetable oil, and skim milk powder, thestructure of V-EY remained relatively stable and hadno cracks after 14 d of storage. The sensory evaluationresults found that the total score of V-EY (62) wasonly lower than M-EY (65) and significantly higherthan that of yogurt made with skim milk powder. Theemulsion gel addition improved the sensory qualitiesof yogurt. Whey protein emulsion gel microparticlesprepared from vegetable oil can be applied to low-fatyogurt to replace fat and improve texture and sensorydefects associated with fat reduction.
NETL
NSTL
Elsevier